To elucidate genetical and biochemical characters of the white egg strains preserved in National Sericultural and Entomology Research Institute(NSERI), RDA of Korea, the genetic segregation ratios in egg colours were investigated by crossing test, and egg pigment precursors were also analyzed by paper chromatography and UV-spectrophotometer scanning. The result obtained by crossing test between the white egg strains and normal one illustrated that the most of white egg strains showed typical segregation ratio of white egg-2(w-2), while maternal inheritance which can be seen in white egg-1(w-1) was not found in any white egg strains. Paper chromatographic analysis showed that egg extracts of all the white egg strains contained 3OH-kynurenine, while kynurenine which is known to existed in white egg-1(w-1) could not be detected at all. From the results of these experiments, it was found that all the white egg strains preserved in NSERI were classified as the white egg-2(w-2) strain.